<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>
<body>
  <script>
    // 用户输入弹框
  while(true){
    let uname =prompt(`请输入用户名`)
    let  password = prompt(`请输入密码`)
    if(uname === `admin` && password ===`123456`){
         alert(`用户登录成功`)
         breal
    }
  }
  </script>
</body>
</html>